Graywater Use by Urban Households: a sustainability issue DAVID ZAHLER GEO 300 Environmental Conservation OLGA Oregon Legal Graywater Association

OutlineOutline The SceneThe Scene OLGAOLGA –Mission –Vision ConservationConservation –Water Use –Potential benefits –Other Conservation Measures –Graywater Rules ConclusionsConclusions

Graywater:Graywater: –Water from laundry, bathtub, shower and (some) sinks; –Water that has been used and is no longer drinkable; –BUT, graywater has NEVER come in contact with human waste OLGA wants to use this graywater for irrigation purposesOLGA wants to use this graywater for irrigation purposes The Scene

2003 Corvallis Pop: 50, Corvallis Pop: 50,000 In years: 60-80,000In years: 60-80,000 Water sources:Water sources: –Rock Creek –Willamette River –Groundwater: 5 wells

Water Use by Customer ClassWater Use by Customer Class Source: Mark Taratoot, Corvallis Public Works The Scene OLGA

Projection of Water Demand by PopulationProjection of Water Demand by Population Source: Economic and Engineering Services, inc The Scene

Projection: Anticipated rate of water withdrawal from the Willamette RiverProjection: Anticipated rate of water withdrawal from the Willamette River Source: Economic and Engineering Services, inc The Scene

Projections based on current Urban Growth BoundaryProjections based on current Urban Growth Boundary Changes in use patterns of any or all customer classes would change future water demandChanges in use patterns of any or all customer classes would change future water demand Other unforeseen changes may reduce future water demandOther unforeseen changes may reduce future water demand –City of Corvallis is exploring the possibility of recycling treated wastewater The Scene

Corvallis can produce enough drinkable water to support population projectionsCorvallis can produce enough drinkable water to support population projections But… single family dwellings are a major consumer of this water, and a significant volume is used for reasons other than drinking or eatingBut… single family dwellings are a major consumer of this water, and a significant volume is used for reasons other than drinking or eating “Graywater” can be used as/considered a resource, not a waste item“Graywater” can be used as/considered a resource, not a waste item The Scene

Organizational Vision Statement:Organizational Vision Statement: –…dedicated to the creation of sustainable Oregon Communities with respect to water use. –Water use as an important indicator for sustainability: A gallon used twice is a gallon that stays unprocessed in our waterways;A gallon used twice is a gallon that stays unprocessed in our waterways; Energy used for water transport and purification is reduced; Energy used for water transport and purification is reduced; City saves money on water coming and going;City saves money on water coming and going; OLGAOLGA

One gallon of graywater used by urban households is one gallon of potable water reserved for its highest and best use—human consumption. OLGAOLGA

Organizational Mission Statement:Organizational Mission Statement: … assist the State of Oregon to develop, test (through household demonstration sites), and adopting graywater use regulations that facilitate reduced water consumption in urban households through safe, effective, graywater use. OLGAOLGA

Household Water Use for an Average Home:Household Water Use for an Average Home: ConservationConservation

ConservationConservation Blackwater Sources (?)

Household Water Use for an Average Home:Household Water Use for an Average Home: ConservationConservation “Easy” Graywater Sources (some faucets)

Graywater Savings:Graywater Savings: –Use 9 gallons/person/day from showers –Use 5 gallons/person/day from faucets –Use 10 GPD from clothes washer… –…to water your garden perennials, you conserve about 25 GPD for “highest and best use” … 60 gallons per day in an average household! ConservationConservation

Other Conservation Measures: SAVINGSOther Conservation Measures: SAVINGS –Install high efficiency toilet: 10 GPCD –Install efficient showerhead: 3 GPCD –Install efficient clothes washer: 5 GPCD –Fix leaks! 5 GPCD TOTAL Savings:23 GPCD The irony: Increased efficiency leads to less available graywater for irrigation purposes.The irony: Increased efficiency leads to less available graywater for irrigation purposes. ConservationConservation

Graywater Rules:Graywater Rules: –Defines how a system should be constructed ConservationConservation

Graywater Rules:Graywater Rules: –Defines how a system should be constructed –Defines where a system can be constructed ConservationConservation

Graywater Rules:Graywater Rules: –Defines how a system should be constructed –Defines where a system can be constructed –Defines when a system can be used ConservationConservation

Graywater Rules:Graywater Rules: –Defines how a system should be constructed –Defines where a system can be constructed –Defines when a system can be used –Defines how graywater is applied ConservationConservation

Graywater Rules:Graywater Rules: –Defines how a system should be constructed –Defines where a system can be constructed –Defines when a system can be used –Defines how graywater is applied –Defines graywater and what nasty things shouldn’t be in it ConservationConservation

Graywater Rules:Graywater Rules: –Such rules can make graywater use for irrigation purposes safe and part of the water conservation “toolkit” for urban households ConclusionConclusion

The State of Oregon, through DEQ rules, can proactively change the culture of domestic water consumption through safe, legal graywater use. ConclusionConclusion